The ink jet print head of an ink jet printing apparatus generally consists of an orifice plate containing orifices or injection parts for discharging ink for recording on a substrate, ink passageways connecting the orifices to an ink supply and an energy imparting device for ejecting ink from the print head through the orifices. The energy for discharging the ink during recording is generated in most cases by resistance elements or piezoelectric devices.
Methods for making the ink passageways for ink jet print heads include, for example, forming fine grooves in a thin layer of glass, metal, or plastic by cutting or etching and then bonding another thin layer of material onto the layer having such grooves formed thereon to form liquid passageways. Another method involves forming grooves in a photosensitive resin coated on a substrate containing the energy imparting device by photolithographic techniques. Once the grooves are formed in the photosensitive resin another thin layer of material is attached to the grooved resin to form, for example, nozzle plates.
Negative photoresists are materials that become insoluble in developing solutions when exposed to optical radiation. The epoxy based negative photoresists are typically very rigid, and as such are susceptible to cracking during manufacturing of the print heads. As such, there is a need for negative photoresist formulations with increased flexibility and crack resistance.